Expansion chamber



June 5, 1934.

F. G. BOVARD EXPANS ION CHAMBER Filed Dec. 15, 1931 INVENTOR f7oyd 6'.80mm ATTOR EY Patented June 5, 1934 PATENT @FFICE EXPANSION Floyd G.Bovard, Akron Ohie Brass Cempany, poration of New Jersey ApplicationDecember 15,

Claims.

This invention relates to bushing insulators and other devices to befilled with a liquid and has for one of its objects to provide a plenumor expansion chamber for the contained liquid in which 5 the surfacelevel of the liquid may be readily observed.

Another object of the invention is to provide an expansion chamberhaving glass walls and an outer metal housing which will protect theglass walls both from mechanical injury and from electrical dischargeand yet permit the surface level to be seen.

Another object of the invention is to provide an expansion chamberhaving glass side walls and means for maintaining a liquid tight jointbetween the side walls and the other portions of the expansion chamber.

Another object of the invention is to provide a device of the classnamed which shall be of improved construction and operation.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combination and arrangement of partsshown in the accompanying drawing and described in the follow ingspecification, and it is more particularly pointed out in the appendedclaims.

In the drawing:

Fig. 1 is a part elevation and part section showing one embodiment ofthe present invention.

Figs. 2 and 3 are fragmentary sectional views showing modifications ofthe invention.

In Fig. l the numeral designates the upper end of a bushing insulatorsurrounding a conductor 11. An expansion chamber is mounted on the topof the insulator and provided with a base plate 12 which rests on theupper end of the bushing 11 having a gasket 13 interposed between thebushing and the plate to form a tight joint. The plate 12 is held downupon the gasket by the conductor 11 and springs 14 which engage a plate15 held by a nut 16 threaded on the upper end of the conductor 11. Theplate 12 has an upwardly extending side wall 17 formed integraltherewith; the side wall being provided with windows 18 through whichthe interior of the expansion chamber and the surface level of theliquid therein may be observed. The conductor 11 fits loosely in theopening in the base plate 12 to permit communication between theinterior of the bushing 10 and the interior of the expansion chamber.The base plate 12 is provided with a seat 19 for receiving the lower endof a glass cylinder 20. As gasket 21 is interposed between the lower endof the cylinder and the seat 19. A cover CHAMBER Ohio, assignor to TheMansfield, ()hie, a cor- 1931, Serial No. 581,144

22 rests upon the upper end of the cylinder 20 and is provided with aseat 23 fitting the top end of the cylinder. A gasket 25 is disposed inthe seat 23. The cover 22 is held to the side wall 17 by screws 26 orother suitable means A terminal member 27 is secured to the upper end ofthe conductor 11 and is provided with a weather shed 28 to prevent theentrance of moisture into the expansion chamber. A filling plug 29 maybe provided in the cover 22 through which the bushing and expansionchamber may be filled.

It will be observed that the wall 17 of the compression chamber is bowedoutwardly. This imparts a degree of resiliency to the wall so that whenthe cover plate 23 is tightened down upon the glass cylinder 20 it willbe held down by a spring pressure exerted by the wall 17. The amount ofresiliency may be regulated by the thickness of the wall and the widthof the wall sections between the windows 18. This resiliency will insurepressure upon the gaskets 21 and 23 at all times irrespective ofdiiierential expansion and contraction between the metal and glass partsand any compression of the gaskets which may take place in time. Theoutwardly curved wall also protects the glass against mechanical injuryand against electrical discharges which otherwise might shatter theglass.

Sometimes difficulty is experienced in expansion chambers of this kindwhich are made entirely of cast metal due to porous castings. In thepresent invention the only portion of the casting which need be liquidtight is the lower plate 12 which is ordinarily thicker than the sidewalls, and since this part of the casting will usually be formed in thebottom of the mold, there is less danger of poor structure in this partthan in the side walls of the casting.

In the modification shown in Fig. 2, the side wall 30 is formed as aseparate piece from the bottom plate 31 and is provided with an inwardlyprojecting flange 32 at its lower end, which engages a shoulder 33 onthe plate 31. This permits the base plate and side wall to be cast orotherwise formed separately to facilitate manufacture and assembly.

In Fig. 3 the side wall 34 is formed separately from the base plate, asin Fig. 2, but in this case the bottom and top plates are held togetherby through bolts so that the only function of the side wall 34 is toform a protecting shield for theglass.

I claim:

1. An expansion chamber comprising a base plate, resilient side wallssecured to said base plate, a glass housing, and means secured to saidside walls for exerting pressure on said glass housing to hold saidglass housing in place.

2. An expansion tank comprising a base plate, a glass housing restingupon said base plate, packing interposed between said base plate andhousing to form a tight joint, resilient side walls secured to said baseplate, and a cover attached to said side walls and bearing upon theupper end of said glass housing.

3. An expansion chamber comprising a metal base plate having a seatthereon, a glass housing open at its top and bottom and having its lowerend resting upon said seat, outwardly bowed side walls secured to saidbase plate and disposed outside of said glass housing, and means securedto said side walls for bearing upon the upper end of said glass housingto press said housing upon its seat.

4. An expansion chamber for a bushing insulator comprising a glasshousing, a cover for said housing, and outwardly bowed metal side wallssurrounding said housing and having a window therethrough, said coverbeing secured to said metal side walls and resiliently held thereby inposition on said glass housing.

5. An expansion chamber for a bushing insulator comprising a metal baseplate having a seat thereon, a glass housing having its lower endresting on said seat, outwardly bowed side walls secured to said baseplate and disposed outside of said housing and having a window therethrough, a cover for said expansion chamber resting upon the upper endof said housing and means for securing said cover to said outwardlybowed side walls and for pressing said cover upon the upper end of saidhousing so that the resiliency in said outwardly bowed side wallsmaintains a tight joint between said cylinder and the seat on said baseplate.

FLOYD G. BOVARD.

